A simple idea - makes it so easy. Just plug it into a midi-connector of a mounted unit of your rack (OUT or THRU) - and the LED will light up and helps you when you need to look into the backside of a rack on dark stages, studios etc.Lenght: 150 mm (MGL1) / 350 mm (MGL2)Connector: 1x DIN 5-pin (Midi output)